1. Field of the Invention
This invention relates to a novel L-amino acid oxidase having very high substrate-specificity with respect to L-lysine, that is, an L-lysine .alpha.-oxidase.
This invention also relates to microbiological production of the L-lysine .alpha.-oxidase.
2. Description of the Prior Art
Hitherto there have been reports on the presence of L-amino acid oxidases in microorganisms, snake venom, the rat kidney, the fowl liver, and invertebrates (Arch Biochem, Biophys. Vol 146, p.p. 54-63, 1971; Journal of Bacteriology, Vol 121, No. 2, p.p. 656-662, February, 1975; and the Tanpakushitsu.Kakusan.Koso, Vol. 17, No. 1, p.p. 42-55, 1972). An L-amino acid oxidase having very high substrate-specificity to L-lysine has never been known in the art. In other words, known L-amino acid oxidases exhibit only very low enzyme activities to L-lysine except that an L-amino acid oxidase preparation derived from the turkey liver exhibits a high activity to L-lysine. However, the turkey liver enzyme also effectively oxidizes several amino acids other than L-lysine, such as L-arginine, L-histidine and L-ornithine. Thus, the oxidase preparation can not be considered to be an enzyme having especially high substrate-specificity to L-lysine.
As L-aminoacid-degrading enzymes having antitumor properly, L-asparaginase (the Tanpakushitsu.Kakusan.Koso, Vol. 15, No. 5, p. 515, 1970); L-glutaminase (Nature, Vol. 227, p. 1136, 1970, and Science, Vol. 172, p. 732, 1971); L-phenylalanine ammonia-lyase (Cancer Res., Vol. 32, p. 285, 1972, and vol. 33, p. 2529, 1973); L-methionine .gamma.-lyase (Cancer Res., Vol. 33, p. 1866, 1973); L-tyrosine phenol-lyase (Cancer Res., Vol. 36, p. 167, 1976), L-leucine dehydrogenase (FEBS Letters, Vol. 33, p. 286, 1973); threonine deaminase (Cancer Res., Vol. 37, p. 2523, 1977); and the like are known. There has been no report, however, that L-amino acid oxidases have antitumor property.